Pros:
Less costly construction for low-volume production, resulting in lower original-build purchase price.
Most likely to be stronger.
No worry about failure of non-fiberglass "fillers" in decks and wherever.
(Let's not talk about wooden boats.)

Cons:
Annual paint touch-up needed to stay on top of any rust.
Likely to be heavier (comes with being stronger), but that's not a problem with a not-to-exceed-hull-speed boat.

Steel versus fiberglass was not part of my boat selection criteria. Nevertheless, most all commercial boats are made in steel for some reason.

One of the topics that always comes to the surface when discussing steel hulls is rust. Yes, rust can be and is a problem with steel hulled boats that were not properly painted and or not properly maintained.

You'll also find that most of the negative comments regarding steel hulled boats and rust come from those not truly in the know. To give you some credible information on the topic of rust and steel hulled boats here's a quote from a designer of serious ocean going boats, Tad Roberts (Note: He's also a well respected member here on TF):

"Once upon a time it was a terminal problem. Today with modern coatings, if properly cleaned, primed, and applied, there is no problem. Rust only appears where the coating has failed. All wear points like rub rails, cleats & bitts, hawse pipes, cabin edges, etc. should be stainless steel and radiused."

A lot depends on the size of the boat. For smaller boats (<35-40'' or so) there is a big weight penalty for a steel hull. That extra weight means that more power is needed for a given speed. In other words, a more costly engine than for an equivalent size glass boat. For larger boats the cost penalty goes away.

The next area of concern is corrosion. Ideally a steel hull needs to be properly coated inside as well as outside. Improper or no interior coating can lead to the boat rusting from the inside out. I have seen more than one steel boat with this problem.

Steel is also a better heat conductor than glass, so steel hulls need to be insulated or they will have significant condensation problems in colder water.

Construction methods and quality are also major considerations, but that is true with glass boats too. For a steel hull, the grade of steel used is significant. Mild steel will have a pretty short life if the coating system fails. You also need to be concerned with topsides weight. A steel house is heavy where you don't want weight. Many boats deal with this by using an aluminum house, but that introduces new corrosion problems if the paint fails at the steel-aluminum junction.

Finally cost - a steel hull can be cheaper than glass for a one off if the hull is hard chine and has only minor plate curvature that can be bent in during construction. If the hull has a round chine and requires shaped plates, the cost of construction will be MUCH greater. It is very expensive to shape steel plate.

Personally, for the size boats most of us have I see no real benefit to steel, unless you want an ice capable boat.

Can problem rust areas be treated with Ospho. It pickles the metal; as my dad use to tell me. He and I have used it on rusting items many time and a little goes a long way. I've had to 2 litter jug now going on 25 years .After treating a rusted surface and the pickling effect set in, the treated surface would never rusted again. Treated areas didn't even need painted after treatment. It does turn the treated area black though and will eat concrete if spilled on it...lol.

Can problem rust areas be treated with Ospho. It pickles the metal; as my dad use to tell me. He and I have used it on rusting items many time and a little goes a long way. I've had to 2 litter jug now going on 25 years .After treating a rusted surface and the pickling effect set in, the treated surface would never rusted again. Treated areas didn't even need painted after treatment. It does turn the treated area black though and will eat concrete if spilled on it...lol.

No treatment is perfect or lasts forever....otherwise everyone would know about it and use it.

Many rust converter products work pretty well if meticulous with prep and application and last if the over coating is good.

The interior out of sight places would concern me. We hear that steel diesel tanks are a worry after 15 years either from inside or outside rust. What protects steel frames and welds in damp locations.

As for hull material, I would like aluminum or steel! You have to paint the hull, but you have to buff fiberglass, so it's an equal trade. But the metal is tougher than fiberglass and more forgiving if you happen to meet a bottom lol.

52 years on my steel hull and still going strong. I have replated a few areas but those were primarily due to previous doublers installed. I have had no issues with the 2400 gallons of fuel tankage, but did with the water tank top.. Yes, you do use more zincs, about every eight feet along the hull. Steel/Alum. connection has been and will always be a problem.

Can problem rust areas be treated with Ospho. It pickles the metal; as my dad use to tell me. He and I have used it on rusting items many time and a little goes a long way. I've had to 2 litter jug now going on 25 years .After treating a rusted surface and the pickling effect set in, the treated surface would never rusted again. Treated areas didn't even need painted after treatment. It does turn the treated area black though and will eat concrete if spilled on it...lol.

Yes, Ospho can and should be used. It chemically changes rust into magnatite. I still would top coat any area that has been Ospho treated. I agree that many of the people who don't like steel, have little to no experience with it. Like any other material, it has its own pros and cons.

Hi all,
Looking at purchasing a Trawler and was looking for the pro's & con's on steel hulls.

Well, what kind of steel trawler?

Cape Horn

Dutch Built

Defever, Garden, etc.

Converted fish boat

Quote:

Originally Posted by bankerboy1

Can problem rust areas be treated with Ospho.

And from a previous post:

Quote:

Originally Posted by bankerboy1

I know this is a loaded question, so here goes....How difficult to is to restore a boat that sunk... I will be doing 90% of the work myself, plus the price is right for the boat. I'm purchasing it from a Salvage company.

I'm going to go out on a limb here and guess it's not a steel trawler yacht, but a 30 to 50 year old (ex) fishing boat in very rough shape. So the discussion about properly prepared and maintained modern steel yachts doesn't really apply. There ARE some great advantages of steel, including the ability to build-in deck fittings like fairleads, integral tanks, structural support for deck cranes and paravanes, et cetera.

And then there's fitment for use: if it's a fish boat then probably every single piece of gear would be inappropriate for a cruising trawler.

Construction methods are crucial to determining the longevity of a coating systems. If attention is made to the ability of the structure to shed water that goes a long way toward the ease of maintaining a coating. As does the ability of the builder to eliminate sharp corners and edges, these are easily chipped and allow corrosion to start. Tanks should be lined and internal spaces provided with insulation and ventilation to eliminate sweating and excess moisture. You can build a good or bad boat from almost any material. I like steel due to it's strength and ease of repair. I've seen steel boats go through things that other boats may not want to have done.

The interior out of sight places would concern me. We hear that steel diesel tanks are a worry after 15 years either from inside or outside rust. What protects steel frames and welds in damp locations.

Food for thought: Fiberglass tanks don't seem to fail but steel does.

Nobody seems to like your question but I'd want that answered before considering a steel boat. Those that like steel boats would tend to not like that question I think. On my FG boat there are many many places that I can't see and/or touch. Mirrors could help but not much I suspect.

I have a theory though. If you can't see it or touch it most sources of abrasion would most likely not be present. How are you going to gouge or scrape off a protective coating if you can't reach it? Perhaps there are robots that could do maintance in these places. I've had quite a few inside my body. That reminds me ... there's something that rattles behiend my port water tank.

In the early 50s there was a boat called a Steelcraft. 26' and a good looking boat. They sold quite a few but petered out.

Most steel tanks of any size (say fifty gallons or more) have or should have an access hatch that unbolts allowing you to inspect, clean or repair the interior. In the past we used coal tar, but modern coatings such as MDPE can be used as an effective lining that lasts quite a long time, I'm not sure how long because I'm not aware of a failure. Even in the old days steel tanks lasted a long time if provided with a water trap at the outlet to prevent water from sitting on the bottom, a feature that should still be employed today.